September weather forecastHarvey, IL
September
Weather in September
The first month of the autumn, September, is still a warm month in Harvey, Illinois, with an average temperature varying between 58.3°F (14.6°C) and 73.9°F (23.3°C).Temperature
Harvey's September weather shows a modest shift in high-temperatures, falling from August's 80.1°F (26.7°C) to a still warm 73.9°F (23.3°C). Harvey temperatures generally rest at a low of 58.3°F (14.6°C) during the September nights.Humidity
The average relative humidity in September is 76%.Rainfall
In Harvey, during September, the rain falls for 13.4 days and regularly aggregates up to 2.48" (63mm) of precipitation. Throughout the year, there are 155.6 rainfall days, and 31.3" (795mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:23 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:33 pm CDT.
Sunshine
In Harvey, the average sunshine in September is 8.8h.UV index
In Harvey, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Harvey, IL
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in September: 58.3°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Harvey, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Harvey, IL
- Average wind speed in September: 7.3mph
The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in September
Harvey, IL
- Average humidity in September: 76%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Harvey, IL
- Average rainfall in September: 2.48"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").
Average rainfall days in September
Harvey, IL
- Average rainfall days in September: 13.4 days
The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in September
Harvey, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Harvey, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Harvey, IL
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Harvey, IL
- Average sunshine days in September: 14 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).
Average UV index in September
Harvey, IL
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Harvey, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Harvey, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
